沉水植物对中华绒螯蟹生长和非特异性免疫力的影响

从东太湖采集伊乐藻(Elodea canadensis)、金鱼藻(Ceratophyllum demersum)、轮叶黑藻(Hydrilla verticilla-ta)、苦草(Vallisneria natans)、马来眼子菜(Potamogeton malaianus)5种沉水植物分别制成干粉。在基础饲料中添加15%的干粉形成5种不同的配合饲料,分别饲喂体重为(9.37±0.15)g的中华绒螯蟹(Eriocheir sinensis)60 d,分析沉水植物对中华绒螯蟹生长和非特异性免疫力的影响。结果显示:马来眼子菜组的中华绒螯蟹平均增重率显著低于对照组(P<0.05),饲料系数显著高于对照组(P<0.05),其余4种沉水植物组的平均增重率和饲料系数与对照组无显著差异(P>0.05);各组成活率、肥满度及肝体比差异不显著(P>0.05)。沉水植物各组的蟹血清超氧化物歧化酶活力显著高于对照组(P<0.05);与对照组相比,轮叶黑藻组、伊乐藻组和苦草组的中华绒螯蟹血清溶菌酶活性显著升高(P<0.05),金鱼藻组和马来眼子菜组则差异不显著(P>0.05);除马来眼子菜组降低外,其余4种沉水植物组中华绒螯蟹对嗜水气单胞菌的抵抗力强于对照组。因此,除马来眼子菜以外的4种沉水植物对中华绒螯蟹的生长性能无明显的促进作用,但可在一定程度上提高其非特异性免疫力。

Effects of submerged plants on growth performance and non-specific immunity of Chinese mitten crab (Eriocheir sinensis)

The five submerged plants,Elodea canadensis,Ceratophyllum demersum,Hydrilla verticillata,Vallisneria natans and Potamogeton malaianus,were collected in East Lake Taihu,and made into dry powders.The dry powders were then incorporated into a basal diet by 15%,respectively,to obtain 5 different mixed diets,and were used to feed Chinese mitten crab(Eriocheir sinensis) weighing(9.37±0.15) g for 60 days.The effects of these submerged plants on growth performance and non-specific immunity of Chinese mitten crab were examined.The results showed that the average weight gain rate(WGR) of Chinese mitten crab in P.malaianus fed group was significantly lower than that in control group(P<0.05),but,on the contrary feed coefficient(FCE) was significantly higher(P<0.05).No significant differences in the average WGR and FCE were found between Chinese mitten crabs in groups fed with the other four plants and those in control group(P<0.05).Moreover,no significant differences in survival rate,body fatness,and hepatosomatic index were observed among treatment and control groups(P>0.05).Superoxide dismutase activity was found to be significant higher in the serum of crabs fed with submerged plants than in that of control(P<0.05).Compared with control group,feeding with H.verticillata,E.Canadensis,or V.natans made the lysozyme activity in serum increased significantly(P<0.05),while feeding with C.demersum or P.malaianus gave no significant differences(P>0.05).Chinese mitten crabs fed with all submerged plants except P.malaianus showed more resistant to Aeromonas hydrophila infection than did crabs in control group.So except P.malaianus,the four submerged plants enhance the non-specific immunity of Chinese mitten crab to a certain degree,though they showed no obvious growth-promoting effects.